Tire industry not only boasts its long history but also writes modern civilization. Since disclosure of pneumatic tires in 1855, the tire manufacturing technology at present has been constantly improved after several technical and theoretical changes. Tire products are widely applied to fields such as transportation. With rapid development of the automobile industry and expressway, the tire has become one of the polymer products enjoying the highest yield and most advanced technological level. However, social development and environment problems such as increasingly serious energy consumption, an increase of accidents, lots of solid tire wastes caused by short service life put forward high requirement on tire. Correlations between energy consumption and rolling resistance, between safety and wet-skid resistance and between service life and wear resistance have formed a “Devil's Triangle”, and the balance of the three correlations cannot be achieved under existing materials and process conditions. Therefore, the development of a novel material is imperative.
Unlike plastics with high degree of crystallinity and high glass transition temperature, rubber materials feature large free volume, small intermolecular force, low glass transition temperature and amorphous high-elastic state. Therefore, most of the rubber materials cannot be applied before filler reinforcing. Carbon black serving as the traditional reinforcing filler was applied more than 100 years ago. Due to its original nano-size, the carbon black can obviously increase physical and mechanical properties, wear resistance and fatigue resistance of the rubber materials, however, main strong physical interaction exists between the carbon black and the rubber; therefore, in spite of advantages such as good nano-reinforcing effect and high wear resistance of the tire, it causes high material dynamic loss and thermogenesis, as well as high tire oil consumption due to the frictions between carbon black particles and rubber molecules as well as between the carbon black particles. Carbon black is well known for its use in preparation of “green tires” because of a large amount of silicon hydroxyl existing on the surface of the white carbon black, brings a good chemical surface modification, can form strong chemical bonds with the rubber and contributes to obvious reduction in rolling resistance of the prepared tire. However, due to small nanoparticle size of the white carbon black, low apparent density of aggregate, and high viscosity of the rubber, the white carbon black is difficultly mixed and is easy to fly, and causes high mixing energy consumption. Meanwhile, organic modification of the silicon hydroxyl of the white carbon black may be performed only after a certain time of high-temperature (140-160° C.) mixing, a modification effect cannot be achieved when a temperature is too low, and a rubber polymer chain may be thermally degraded when the temperature is too high. Therefore, the process has extremely high requirements on performance parameters of processing equipment, processing cost is high, and the tire prepared from the white carbon black has poor wear resistance. The abovementioned reasons hinder its large-scale application.
Compared with the traditional rubber material, a polyurethane elastomer material has the characteristics of excellent wear resistance, high tearing strength and elongation, wide hardness range, low rolling resistance, extremely high load capacity and good vibration absorption and shock absorption effects. Particularly, a casting polyurethane elastomer is the most wear-resistant elastomer at present, has advantages of high wear resistance, colorability, high cutting resistance and excellent oil resistance and chemical resistance, does not need to be added with carbon black or aromatic hydrocarbon oil and becomes an ideal material for manufacturing high-performance tire. The tire made from the polyurethane material boasts its simple process, safety, durability and eco-friendly performance, and can be recycled or used for manufacturing other industrial products once scraped, and its cost is much lower than that of the traditional rubber tire. Therefore, the polyurethane tire is well received by consumers and becomes a focus of the industry.
However, at present, there is a need for solving technical problems in production of the polyurethane tires such as poor high temperature resistance and undesirable wet-skid resistant grip ability.